Fig. 6.1
An example of the “hybrid technique”: pins, with a longer thread, are easily joined together by clamps and carbon rods
Going by the results described, we have modified the percutaneous technique: we have started using pins with a longer thread (7 cm), and we have stabilized the pins with an external fixator. These two changes increase the resistance to pullout by a factor of 8; moreover the external fixator reduces the importance of pin configuration in implant stability.
6.3 What Kind of Fractures?
The conditions required for a correct percutaneous technique are a stable closed reduction, a good bone stock, a minimal comminution (particularly involving the tuberosities), an intact medial calcar, and good patient compliance [52].
The two-fragment fractures involving the humeral surgical neck are the most suitable for treatment with this technique [12, 34, 52, 53]: it is reported by various authors that the worst results associated with percutaneous pinning are achieved in fractures involving the tuberosities [34, 54]. Even though different authors report bad results in displaced three to four-fragment fractures [55, 56], recently these fractures have been supposed to be increasingly suitable for the percutaneous technique [15, 42], especially in cases of valgus impacted fractures [57–60].
The patient’s age is an important aspect. Some authors recommend this surgical treatment when the patient is young because of high bone quality [41]. But Calvo, referring to three-fragment fractures, states that young patients are better suited to open reduction and internal fixation because better reduction can be achieved, while for older patients closed reduction and external fixation may be sufficient [34]. Also Carbone, dealing with a particular implant called MIROS, states that percutaneous pinning is a good choice for older patients [61].
6.3.1 Authors’ Opinion
We believe the majority of fractures can be treated with pins, either with a closed technique or with an open one: in fact, even in cases of complex fractures, the surgeon can perform an open reduction followed by percutaneous osteosynthesis. Hertel has focused our attention on the medial hinge [62], but its continuity does not strictly correlate with the humeral head blood supply [63], especially in young patients (up to the age of 60). In fact the possible avascular necrosis can be completely asymptomatic; in cases of disability it can be treated with a prosthesis. Moreover joint replacement is easier without any hardware to be removed.
This technique is contraindicated in cases of:
Fractures without a good lateral cortex where the pins are introduced and engage.
Splitting of the humeral head : it is a relative contraindication because the risk of avascular necrosis is high; however, Resch believes that young patients with an AOC3-type fracture deserve an attempt at osteosynthesis [33].
Tuberosity highly comminuted: the fragments must keep their anatomic integrity.
Fractures with diaphysis involvement: it is a relative contraindication because a different pin configuration described below can get round this problem.
6.4 Surgical Technique and Postoperative Care
The main steps of this procedure are two, as described by different authors: the closed reduction using the C-arm (we referred to the Chap. 4) and the percutaneous fixation.
The operation is usually performed under general anesthesia, but the interscalenic block is also a good option [15, 33, 42, 61].
Correct patient position is mandatory. Even though some surgeons prefer the lateral position [35], usually we have to choose between the supine position and the “beach-chair” position to perform the deltopectoral approach. Some authors use pins as joysticks during the reduction maneuvers [64–66].
Nowadays we know that pins must be terminally threaded. Different diameters are used: 2.5 mm pins are the most used [12, 31, 36, 41, 42, 52, 67], but also the 0.3 mm [43], 2 mm [31], 2.8 mm [9], and 3 mm [64] ones are suitable. Surgeons usually refer to Jaberg’s technique regarding the number of pins to be placed: he states that the percutaneous osteosynthesis needs at least three pins (five pins in cases of three-fragment fractures involving the greater tuberosity), two laterally and one anteriorly [12]; the anterior pin is challenging, mainly because of the anterior structures it can injure [29]. Percutaneous pin placement options include retrograde lateral, retrograde anterior, retrograde anterolateral, antegrade through the humeral head, antegrade posterolateral through the greater tuberosity, and antegrade superomedial through the lesser tuberosity, depending on the fragments displaced [34]. Other authors use only antegrade pins [67].
Herscovici et al. [19] stresses three important technical points:
The starting point of the pins should be at least 2 cm distal to the fracture.
A wide pin spread should be performed.
The pins should reach, but not go through, the subchondral bone.
The surgeon placing the pins must remember the humeral head retroversion (about 20°). They should be angled approximately 45° to the shaft in the coronal plane and 30° to the shaft in the sagittal plane [41]. Some authors suggest cutting and bending the pins beneath the skin to reduce the risk of infection and mobilization [19, 42, 43].
6.4.1 Augmentation of Pins by External Fixation
Pins can be used as external fixator fiches [68, 69], and this is a good option in cases of complex fractures [65]. Over the years we have stopped using bulky implants such as the Hoffman external fixator [49, 65, 68–70], and now we prefer more compact ones [64, 66]. The basic principle is still the classic external fixation as a bridge between the fracture stumps stabilizing after performing the reduction.
6.4.2 Authors’ Opinion
Basing ourselves on the biomechanical study illustrated above [51], we have modified the percutaneous technique by introducing the so-called hybrid technique : it is based on the basic pinning principle (pins, with a longer thread, must go through the fracture) associated with an external fixator. Pins are easily joined together by clamps and carbon rods. Then we compared this surgical technique with the classic one in cases of two-/three-/four-fragment fractures: the results we achieved after 12 months of follow-up were statistically better in the group treated with the new technique, mainly with regard to complications (6 vs 16), revision rate (4 % vs 19 %), pin migration rate (1 vs 8), and modified Constant score (89 ± 9 vs 77 ± 14) [71].
6.4.2.1 Postoperative Care
The protocols described in the literature generally state that immediately after surgery, the arm is immobilized in adduction in a simple sling (an abduction sling does not seem necessary [15]) generally worn for 3–4 weeks [9, 12, 35, 36, 42]. Some authors postpone passive exercises until the patient stops wearing the sling, while other authors recommend passive exercises and pendulum exercises from the day after surgery [15, 41, 64, 67]. Instead there is considerable variability as regards the active exercises: from the first to third weeks [64], from the fourth [15], from the sixth [57], and from the seventh [34]; Ebraheim uses the mini-external fixator and lets the patient move their arm actively even from the first day after surgery [66].
Pins are usually removed in the outpatients’ department, under local anesthesia if necessary [15], but some prefer to remove them in the operating room under sedation [9]. Removal is usually performed at 3–6 weeks postoperatively [9, 15, 33–35, 42]. Some authors describe removal on two different days, for example, Jaberg removes the tuberosity pins at 3 weeks postoperatively, while other pins at 6 weeks postoperatively [12]; Magovern removes tuberosity pins at 3–4 weeks postoperatively, while other pins are removed at 4–6 weeks postoperatively [52]; Seyhan places only four antegrade pins and removes two of them at 4 weeks postoperatively and the other 2 at 6 weeks after surgery [67]. Other authors describe pin removal at 6–8 weeks postoperatively [64] or even at 9–12 weeks [66]. However, there is no scientific rationale regarding either the best way to wear the sling or the best time to start passive/active mobilization, and no one knows whether late pin removal induces better healing of the fracture. The wide range of pin removal times may depend on the individual surgeon’s familiarity with the fixation system.
6.4.2.2 Authors’ Preferred Surgical Technique
An optimal patient resting position is mandatory and depends on the type of surgery to be performed: closed reduction (supine position ) or open reduction (beach-chair position ). The surgical field must be prepared so that the surgeon can fully move the shoulder and can see and palpate the acromioclavicular joint and the coracoid: these are very important landmarks for the osteosynthesis (Fig. 6.2).
Fig. 6.2
With a dermographic marker the sites of the coracoid, of the coracoacromial ligament, of the deltoid insertion, of the acromion, and of the acromioclavicular joint are highlighted. The lateral longitudinal line is a very useful landmark for the axillary nerve (about 5 cm distal to the lateral edge acromion) and for the first pin starting position (9–10 cm distal to the lateral edge of the acromion, 4–5 cm proximal to the deltoid tuberosity and anterior to the line)
An inaccurate surgical field usually leads to mistakes in the pin insertion point. Osteosynthesis starts after the reduction maneuvers which we have described in the previous chapter (Chap. 4). We prefer using self-drilling and self-tapping pins 300 mm long, 2.5 mm in diameter, and with a thread 7 cm long, even though the long thread has been blamed for causing soft tissue injuries [52]. Two lines on the pins (12 and 14 cm) are useful landmarks during the percutaneous insertion. The system is sold as the “Galaxy Shoulder” (Orthofix Srl, Via delle Nazioni 9, 37012 Bussolengo, Verona, Italy). The assistant must keep the arm parallel to the floor (which is our reference) while keeping the fracture reduced: so the humeral head is posterior to the diaphysis thanks to its own physiological offset. An adequate check with the C-arm is mandatory, mainly when the surgeon is placing the first retrograde pin and the antegrade pins. The first pin starting position is 9–10 cm distal to the lateral edge of the acromion, 4–5 cm proximal to the deltoid tuberosity and anterior to the lateral line parallel to the diaphysis and going through the lateral edge of the acromion (Fig. 6.2).
The pin is inserted 20–25° retroverted and pointing to the tip of the coracoid. The number and starting points of pins depend on fracture type. In the case of a two-fragment fracture, we use four retrograde pins (Fig. 6.3). In three- and four-fragment fractures (without or with low tuberosity dislocation), an attempt at closed reduction may be made; then we need two more antegrade pins to fix the humeral head and the greater tuberosity (Fig. 6.4). The starting point is just lateral to the lateral edge of the acromion and corresponds to the humeral footprint. One pinpoints to the humeral head apex, the other one just beneath the medial hinge.
Fig. 6.3
An example of a two-fragment fracture before surgery (a), immediately after surgery (b), and after 1-year follow-up (c)
Fig. 6.4
An example of three-fragment fracture before surgery (a), immediately after surgery (b), and after 1-year follow-up (c)
Our quite lengthy experience of percutaneous pinning has led us to consider it an alternative treatment to internal fixation even in cases of complex fractures. Some fracture patterns, such as valgus impacted three-fragment fractures, fracture-dislocations, and four-fragment fractures, are best treated with the open approach. The integrity of each anatomic structure is mandatory: osteosynthesis can be performed only if tuberosities are not highly comminuted.
We start with the deltopectoral approach . The first step is to recognize the anatomic structures (long head of the biceps, lesser and greater tuberosity), and an accurate bursectomy can be helpful. The preoperative CT is very useful and helps us to plan surgery and to operate between bone fragments without further damage to the blood supply. In particular we have to look for the greater tuberosity posteriorly and superiorly to the long head of the biceps, while the lesser tuberosity is usually medial to it, often beneath the conjoint tendon. Tuberosities must be held by bioresorbable sutures through tendon insertion. This prevents further comminution of fracture fragments during reduction maneuvers. The correct anatomic reduction can be helped by landmarks such as the greater tuberosity height or the distance between the upper border of the pectoralis major tendon insertion on the humerus and the top of the humeral head (usually around 55 mm [72]). The humeral head is usually rotated showing the surgeon its articular surface and has to be properly replaced. The subsequent surgical steps are quite similar to those of any open reduction technique, but, after positioning the fragments correctly, the first two pins used to fix the head and the diaphysis together must be placed through the skin because they will take part in the definitive osteosynthesis. The C-arm lets the surgeon evaluate the initial correction achieved.
In the case of three- or four-fragment fractures, we augment the fixation with osteosutures of the tuberosities to oppose the traction forces caused by the supraspinatus and subscapularis tendons. We use three nonbioresorbable sutures dec 5: one for the supraspinatus tendon, one for the subscapularis tendon, and one to fix both tendons to the diaphysis (the hole in the diaphysis is made next to the tubercular groove, where bone quality is higher). Then percutaneous osteosynthesis is completed with four more pins: two from the diaphysis to the head with a distal to proximal direction and two from the greater tuberosity toward the medial hinge with a proximal to distal direction. The final fluoroscopic check and the wound suture complete the surgery. The pins are then joined together by the external fixator. Sometimes, depending on fracture type, two more pins can be used as a true external fixator fixing the system to the diaphysis (Fig. 6.5).
Fig. 6.5
In cases of fractures with diaphysis involvement or highly unstable fractures (shown in the pictures), the traditional pinning technique is contraindicated because pins cannot engage both the lateral cortex and the subchondral bone; pins can then be used as a true external fixator
Patients are usually discharged from the hospital within 2 or 3 days of surgery. They wear a shoulder sling which keeps the arm adducted until the pins are removed; this takes place in our outpatients’ department without anesthesia. Active elbow and wrist mobilization is encouraged from the first day after surgery; patients can start pendulum exercises as soon as they can bear the pain. Even though there is insufficient evidence to say when to start mobilization (there is only some evidence to support earlier arm movement for less serious fractures [73]), we believe that, if the pain is controlled, patients should start rehabilitation as soon as possible. Patients undergo a weekly follow-up in our outpatients’ department to have their surgical wounds dressed. Passive mobilization associated with external and internal rotations usually starts 3 weeks postoperatively, while patients are allowed to actively move their shoulder 6 weeks after surgery. X-rays are performed before discharge, 1 week, 6 weeks, and 3 months after surgery.
6.5 Complications
6.5.1 Pin Migration
First reported by Mazet [74], pin migration is probably what surgeons fear most. It rates between 0 and 41 % [9, 34–36, 67, 75]. However, Calvo et al. [34] emphasizes that pin migration resulted in loss of reduction of the fracture in 10 % of patients, and revision surgery was considered only in two patients, even though the migration rate is high in his study (36 %). We do not know why shoulder pins are so prone to mobilization: factors such as muscular activity, respiratory excursion, capillary action, electrolysis, regional resorption of bone, gravitational forces, and the great freedom of motion of the upper extremity are thought to be involved [74, 76, 77]. Cases of thoracic cavity migration have been reported [78], but it must be stressed that there are no reports of migrated Kirschner wires from the proximal humerus to the thoracic cavity causing cardiac tamponade and sudden death [79]. In studies involving an external fixator, the pin migration rate falls between 0 and 6 % [10, 61, 64, 66, 71].
6.5.2 Avascular Necrosis
The risk of avascular necrosis (AVN) is between 0 and 26 % [9, 12, 15, 19, 34, 42, 58, 61, 64], and symptoms or radiographic signs may also occur within 2 years after surgery; so patients should be followed for this length of time [9, 52]. We must keep in mind that:
The development of AVN is determined largely by the injury itself and not necessarily by the course of treatment [80].
The AVN can be absolutely asymptomatic or just partially symptomatic [81].
Only in a few cases of AVN are the functional results so bad that further surgery is needed; Gerber reports that the clinical results for patients with AVN without malunion were as good as those for patients treated with hemiarthroplasty [82].
6.5.3 Infection
Infection rates are between 0 and 10 % for superficial infections and between 0 and 7 % for deep infections [10, 12, 34–36, 42, 43, 64–67, 70, 75, 83]. Usually sequelae do not result from superficial infections, and the problem is easily resolved by pin removal and by using antibiotics if necessary. Only a small number of deep infections usually have to be surgically treated [12, 66]: Shabtai focused his study on infections associated with the use of an external fixator in cases of proximal humeral fractures [83] and shows that all the infections (17 superficial and one deep among 46 patients) healed without surgery. Some authors state that pins should be placed under the skin [52].
Our preferred surgical technique has been criticized because of the risk of infection. So we planned a retrospective multicenter study examining the risk factors potentially associated with infection after various types of proximal humeral fracture fixation. Among the 209 patients who underwent pinning fixation, nine (4.3 %) showed a deep infection and one of these needed further surgery. The factors that correlated with infection were the length of surgery, the preoperative lavage with chlorhexidine gluconate, and the prophylactic antibiotic (it seems better to avoid the use of first-generation cephalosporin in favor of more effective prophylactic therapy). The type of fixation and the type of reduction (open vs closed) did not seem to affect the rate of infection. However, when patients who underwent a plate fixation were compared with those treated with percutaneous fixation, the rate of further surgery needed to treat the infection was lower in cases of percutaneous fixation. Of the five cases that needed further surgery, four had had a plate fixation and one a percutaneous fixation (p = 0.047) [84].
6.5.4 Loss of Fixation
Loss of fixation is the main criticism of the pinning technique and relates to pin mobilization: in fact it usually arises in cases of osteopenic patients and comminuted fractures. Many authors show a rate of 0 % [67, 70], but in Jaberg’s study the rate is 19 % (nine patients), and four cases needed a second closed fixation [12]. Soete et al. [42] and Fenichel et al. [43] report a 13 and 14 % rate, respectively, while Calvo et al. [34] shows five losses of fixation on 74 patients, with two patients who underwent further surgery (one closed fixation and one joint replacement with hemiarthroplasty). The rate of loss of fixation decreases if the surgeon uses the external fixator (0–9 %) [61, 64–66]. In our comparison study of the hybrid technique and the traditional pinning technique, the rate was 2 and 17 %, respectively [71].
6.5.5 Malunion
Malunion has been defined in various ways so it is difficult to compare patients across different studies. For example, Calvo reports a rate of 28 % [34], while Jaberg 19 % [12] and Keener 17 % [57]. The most common residual deformities include varus angulation of the head and posterosuperior displacement of the greater tuberosity [52]. Calvo et al. [34] and Yu et al. [36] performed a radiographic evaluation using a numeric scale: an angulation between 20° and 45° was scored as 1 point, and >45° was scored as 2 points; a displacement between 0.5 and 1 cm was scored as 1 point, and >1 cm was scored as 2 points; if the angulation and displacement were lower than 20° and 0.5 cm, respectively, the quality of reduction was considered excellent and scored as 0 points; the score in each case ranged from a minimum of 0 (in perfectly reduced fractures) to 12 points because the final score for each case was the sum of the scores allocated to each fragment. Calvo reported a mean score for residual deformity of 2.16 ± 1.8 and stated that the score was significantly higher in cases of reduction defects involving tuberosities [34]. Yu reported a mean value of 1.8 ± 1.3 and showed that there was no statistical difference between the immediate postoperative imaging and the final follow-up imaging [36]. It is important to remember that radiographic features may not correlate with clinical results: patients may well tolerate even quite significant failure of bone healing [12, 34, 36, 52].
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